The invention relates to a connecting assembly between a shaft journal and a constant velocity universal joint used, more particularly in the drive line of a motor vehicle. The constant velocity universal joint comprises an outer joint part connectable to a driveshaft, an inner joint part which is engaged by the shaft journal in a rotational fixed way for torque transmitting purposes, as well as torque transmitting elements which are effective between the outer joint part and the inner joint part. The shaft journal can be the input part or the output part of a drive, more particularly of an axle differential or of a transmission, so that the shaft journal is axially and radially fixed. Accordingly, the constant velocity universal joint can be positioned at one end of a propeller shaft. The shaft journal can also be radially elastically supported in an elastic intermediate bearing, with the constant velocity universal joint then being used as the central joint of a two-part propeller shaft.
From DE 10 2004 048 079 A1, there is known a connecting assembly between a constant velocity universal joint which is arranged at the end of the propeller shaft and an axially fixed shaft journal of a gearbox. By means of longitudinal teeth, the shaft journal engages an inner joint part of a constant velocity universal joint in a rotationally fixed way. The propeller shaft comprises a threaded portion on to which there is threaded a threaded sleeve. The threaded sleeve engages a threaded recess of the inner joint part, with a securing ring being arranged in the threaded recess axially fixing the inner joint part relative to the threaded sleeve.
U.S. Pat. No. 4,756,640 proposes a connecting assembly between the inner joint part of a constant velocity universal joint and a shaft journal, using a securing element. The securing element comprises a shoulder which is axially held in an outer annular groove of the shaft journal, as well as a plurality of longitudinally extending elastic fingers which engage an inner annular groove of the inner joint part.
Overall, connecting a constant velocity universal joint to a shaft journal is complicated because, there is available only a limited amount of space and the final assembly stage is also complicated. At the same time, the connecting assembly between the constant velocity universal joint and the shaft journal is subject to optimum safety regulations to prevent disconnection and to ensure minimum adverse effects on the strength of the components.
It is the object of the present invention to propose a connecting assembly between a constant velocity universal joint and a shaft journal, which has s compact design, which permits secure axial fixing conditions and ensures a minimum effect on the shaft strength, with easy assembly and dismantling procedures being ensured as well.
The objective is achieved by providing a connecting assembly, more particularly for use in the driveline of a motor vehicle, comprising a shaft journal with an outer journal groove; a constant velocity universal joint with an inner joint part which is connected to the shaft journal in a rotationally fixed way for transmitting torque, and which comprises a sleeve projection, wherein, in an outer circumferential face of the sleeve projection, there is provided at least one engagement recess; a securing sleeve for axially fixing the inner joint part relative to the shaft journal; wherein the securing sleeve comprises inner holding portions which engage the journal groove, as well as outer holding portions which engage the at least one engagement recess.
The advantage of the inventive connecting assembly is that there are achieved secure axial fixing conditions between the inner joint part and the shaft journal. By means of its sleeve projection, the inner joint part is inserted into the annular chamber formed between the inner holding portions and the outer holding portions of the securing sleeve. This design allows the depth of the journal groove to be minimised, as a result of which the strength of the shaft journal is maximised in the region of the journal groove because the inner holding portions are radially secured against being widened by the sleeve projection of the slid-in inner joint part. The shape of the journal groove can be correspondingly flat, so that the shaft journal experiences only a slight cross-sectional reduction. A further advantage refers to the simple construction of the connecting assembly which comprises only a few parts, which has an advantageous effect on production costs. The connecting assembly requires only a small space, and the components are easily mounted. More particularly, the constant velocity joint can be completely pre-assembled, so that, during the final assembly stage, only the connection with the shaft journal has to be effected.
More particularly, the shaft journal can be the input part or the output part of a drive. If provided in the form of an input part, the shaft journal can be used for example in an axle differential which serves to distribute the introduced torque from the propeller shaft to two sideshafts. If provided in the form of an output part, the shaft journal can be used in a transmission from which the torque is introduced into the propeller shaft. The drive is fitted prior to the driveshaft being mounted, so that the shaft journal is axially and radially fixed in the drive housing.
For mounting purposes, the securing sleeve is slid on to the shaft journal far enough to allow the elastic inner holding portions to engage the journal groove. Then the inner joint part and thus the entire constant velocity universal joint is slid on to the shaft journal until the elastic outer holding portions engage the at least one engagement recess of the sleeve projection. In the slid-in condition, the sleeve projection, by means of its end portion, is arranged radially between the inner and outer holding portions of the securing sleeve. In this way the inner holding portions are prevented from widening radially, so that they are securely held in the journal groove. If viewed in half a longitudinal section, the securing sleeve preferably comprises an approximately C-shaped profile; to that extent, the securing sleeve can also be regarded as an envelope sleeve, with the inner joint part, by means of its sleeve projection being inserted into the annular chamber formed between the inner sleeve portion and the outer sleeve portion. The inner sleeve portion and the outer sleeve portion have a substantially cylindrical shape.
According to a preferred embodiment, there is provided a collar member which is slipped on to the securing sleeve and secures the outer holding portions against radial widening, with the collar member covering part of the sleeve projections of the inner joint part, including the securing sleeve. In its mounted condition, the collar member thus prevents the outer holding portions of the securing sleeve from being elastically bent open or widened radially outwardly, so that the connecting assembly is reliably secured even at high speeds and related centrifugal forces. For fixing the collar member, there can be provided a binding element or a securing ring, with the binding element preferably being designed in such a way that it cannot be closed unless the collar is accurately positioned on the sleeve projection. In this way, secure assembly conditions are ensured.
According to further preferred embodiment, the securing sleeve comprises a radial portion which connects the inner holding portions to the outer holding portions. The radial portion can be provided in the form of a continuous ring or it can comprise radial partial portions which are indirectly connected to one another. The securing sleeve is preferably shaped in such a way that the axial projection of the inner joint part, in the mounted condition, extends as far as the radial portion of the securing sleeve, more particularly, that it can be made to contact same. The radial portion of the securing sleeve thus functions as a stop if axial forces occur between the inner joint part and the shaft journal. The securing sleeve is preferably produced out of plate metal as a formed part. This is advantageous because the securing sleeve can then be produced in a simple way, for example by being turned over out of a circular blank or out of a meander-shaped strip material which is formed into a ring and subsequently welded, or it remains open. Using plate metal is advantageous in that the individual partial portions of the securing sleeve can be flat so that there is required only a small amount of installation space. However, different materials and production methods are also conceivable, such as producing the securing sleeve out of plastics.
According to a first design of the securing sleeve, the inner holding portions are provided in the form of elastic holding fingers which are circumferentially distributed and project from the radial portion in the longitudinal direction. The holding fingers preferably comprise radially inwardly directed engagement projections which are located more particularly at the end of the holding fingers and engage the journal groove. In this way, the inner joint part is axially secured relative to the shaft journal. The outer holding portions preferably comprise elastic holding tongues which engage the at least one engagement recess of the inner joint part. In a concrete embodiment, the outer holding portions each comprise two longitudinally extending side webs and one connecting web connecting same to one another, wherein the elastic holding tongues projecting inwardly from the connecting webs. Thus the circumferentially extending radial portion, the longitudinally extending side webs and the circumferentially extending connecting web form a frame around an aperture into which there extends the holding tongue. The holding tongues are slightly bent inwardly from the connecting web and, by means of their free ends, extend towards the radial portion of the securing sleeve. All the holding tongues engage the engagement recess which is preferably provided in the form of a continuous annular groove. If viewed in a longitudinal section, the profile of the annular groove is approximately adapted to the shape of the holding tongues, with the depth of the annular groove increasing more particularly towards the end of the sleeve projection.
According to a second design, the inner holding portions of the securing sleeve are provided in the form of circumferentially distributed inner holding tongues which extend in the longitudinal direction. The inner holding tongues preferably comprise inwardly directed first projections which engage the journal groove to provide axial security. In half a longitudinal section, the first projections can be provided in the form of bulging portions, preferably arch-shaped bulging portions, with the journal groove then preferably comprising a round or oval profile. The groove depth and the notch effect can thus be minimised, which has a positive effect on the strength of the shaft journal. Accordingly, the outer holding portions are preferably provided in the form of circumferentially distributed outer holding tongues which extend in the longitudinal direction. The outer holding tongues comprise inwardly directed second projections which engage the at least one recess of the sleeve projection to provide axially secured conditions. According to a preferred embodiment, the securing sleeve, in a developed view, is meander-like, with one inner holding tongue following to adjoining outer holding tongues and, accordingly, with one outer holding tongue following two adjoining inner holding tongues. This is achieved in that between each two adjoining outer and inner holding tongues, there are provided longitudinal slots, with the outer longitudinal slots extending into the opposed inner holding tongue and with the inner longitudinal slots extending into the opposed outer holding tongue. In this way, it is possible to achieve an elastic spring effect of the securing ring.
For both designs it is advantageous if the sleeve projection of the inner joint part comprises an inner recess with a preferably cylindrical inner face which delimits a receiving chamber for the inner holding portions of the securing sleeve. The inner holding portions are clamped in between the outer face of the shaft journal and the inner face of the sleeve projection. The inner holding portions are thus prevented from being radially bent open, which could be caused by centrifugal forces or radial forces induced by axial forces, so that the holding portions are securely fixed in the journal groove. At its end, the sleeve projection comprises preferably conical flattened portions in order to permit an easy assembly procedure by inserting the sleeve projection into the securing sleeve. At its outer circumferential face, the sleeve projection preferably comprises a radial projection up to which the outer holding portions, by means of their free ends, approximately extend in the mounted condition of the assembly. The radial projection which can be provided in the form of an annular bead thus forms an axial stop for the securing sleeve. To ensure sealing conditions, it is advantageous if the inner joint part, at its sleeve projection, comprises a continuous annular groove which can be engaged by the inner bead of a sealing member.
The rotationally fixed connection between the inner joint part and the shaft journal is preferably provided in form of a splined connection, other torque-proof connections not being excluded. This applies to all the above-mentioned embodiments. It is proposed that the journal groove which is engaged by the securing sleeve by means of its inner holding portions is arranged so as to axially adjoin the shaft splines. The annular groove is thus easy to produce because it is not positioned inside the shaft splines. The inner joint part comprises a ball track portion in which there are formed inner ball tracks, with the shaft splines axially extending beyond the ball track portion as far as and into sleeve projection. This measure allows the transmission of particularly high torque values.